1. Fill a saucepan with an inch or so of water and bring to a simmer. Use a double boiler, or place a heatproof bowl over the simmering water (making sure the bowl does not touch the water) and melt the chocolate, margarine, and coffee together. Remove from heat and stir in bourbon. Set aside.
2. In a separate heatproof bowl, whisk the two egg yolks with two tablespoons of the sugar over the pan of simmering water. Whisk this mixture until it becomes foamy (cooking it just slightly). When foamy, whisk the egg-yolk mixture into the bowl with the chocolate mixture. Set aside.
3. Beat egg whites with a pinch of salt, gradually adding the remaining two tablespoons of sugar, until stiff peaks form. Fold the stiff egg whites gently into the chocolate mixture.
4. Beat the parve whipped topping until stiff peaks form and then fold into the chocolate mixture. Pour into pie shell and set aside.